br br How many solar panels do I need to produce enough electricity to run my house? br br One question I get all the time from people who are planning to install solar panels to produce electricity is, How many solar panels do I need to produce enough electricity to run my house? br br The answer is that The array size you need depends on your average electrical usage, climate, roof angle, shading problems and many other factors. To approximate the array size you need, multiply your average daily electrical demand in kilowatt-hours by 0.25. The result is the approximate size of solar array, in kilowatts, needed to meet your electrical demand.